Printers for printing desired information such as text and images on sheet-like printing media such as paper and film are in wide use as information output devices in word processors, personal computers and facsimile machines.
In general, a printer is used by being connected to a host device such as a personal computer, data such as images and text to be printed is processed into a form suitable for printing by the printer by means of a printer driver that has been installed in the host device, the processed data is transmitted to the printer together with control data and the printer is caused to print the desired images and text.
Digital cameras have come into widespread use rapidly in recent years and are available in multifarious configurations from those capable of employing interchangeable lenses in a single-lens reflex silver-halide camera to those of small size and weight on which the emphasis is in portability. Memory cards used as the storage media for storing image data also are available in a variety of types having different shapes and interface specifications.
With the growing popularity of image input devices such as digital cameras, so-called direct printers have become the focus of attention. A direct printer has an interface for a storage medium, such as a memory card, for storing image data and is capable of reading and printing an image directly from the storage medium without the intervention of a host device.
Though many of these direct printers are adapted so as to be connectable to a host device, they are constructed in such a manner that when a memory card has been inserted into the printer, the processing necessary for printing the image data that has been stored on the memory card is executed entirely within the printer.
When an image that has been stored on a memory card for which the direct printer does not have a slot that supports this card is to be printed, it is necessary to insert the memory card into the available slot via an adapter or the like in order to achieve conformity with the specifications supported by the direct printer. In recent years, however, there has been an increase in direct printers provided with slots of multiple types for the purpose of supporting various types of memory cards.
Such a direct printer having slots of a plurality of types may be equipped with separate controllers (control ICs) for controlling respective ones of the interfaces that interface the memory cards. In a case where the interfaces for each of these memory cards are controlled by a single controller, the controller is provided with a large number of terminals in order that the memory cards may input and output signals independently of one another.
In general, a direct printer thus provided with slots of a plurality of types is incapable of accessing memory cards of a plurality of types simultaneously regardless of the fact that the printer is adapted to allow memory cards to be inserted into the slots simultaneously. For example, the memory cards are accessed upon establishing an order of priority, such as giving priority to the memory card inserted first.
Accordingly, though a controller in a direct printer having such a structure is provided with a large number of terminals, only some of these terminals are used. This tendency will become more pronounced as the types of printing media used by digital cameras increase, and hence the number of terminals with which the controller is provided will become exceedingly large.
As a consequence, when the controller is fabricated as an IC, the IC becomes large in size and so does the mounting area on a board. Another problem is a marked increase in the cost of the IC.